Opposed-slot spiral scrapers



March 15, 1960 J. c. TRIPPLEHORN v oPPoED-SLOT SPIRAL scRAPERs Filed Sept. 60, 1957 INVENTOR JAMES TRIPPLEHORN ATTORNEYS ilnited States Patent" OPPOSED-SLOT SPIRAL SCRAPERS l James Conrad Tripplehorn, Pampa, Tex. y Application September 30, 1957, Serial No. 687,161

14 Claims. (Cl. 1156-176) A principal object ofthe invention is to provide aV scraper which may be securely installed at any position along the length of a sucker rod between the tool joints present plastic Scrapers from prior art metal devices, the parain having a strong tendency to adhere to the metal Scrapers in the same manner as it adheres to other metal objects located in the Well, such as the tubing and the sucker rod.

Still another object of the present invention is to pro-A vide a plastic paraflin scraper having minimum weight, and having maximum oil-passage clearance so as to permit the maximum flow of oil therepast and the maximum washing effect of the ow of oil in contact with the scraper to reduce paraiiin deposits on the latter.

Another object of the invention is to provide an improved spring clip which may be embedded in the bosses at the ends of the scraper so as to increase the grip thereofl on the sucker rod. This improved clip has been crimped at its longitudinally opposed ends so as to provide iianges which may beV employed to increase the grip of the spring clip while at the s ame time permitting the use of lightergauge metal than would be possible with the purely C- shaped clip. In addition, by using a clip having crimped ends, when the clip is embedded in the plastic, the concave portions of the clip will beheavily coated with the plastic at the ends thereof, such installation being accomplished A without the necessity of altering the standard sucker rod orperforming any operation thereon which might weaken the same, as for instance, welding.

More particularly, it is a principal object of the present invention to provide a plastic scraper having an improved type of frictional rod-engaging structure which structure will be referred to hereinafter as opposed-slot mounting.

It is another primary object of the present invention to provide an opposed-slot scraper which, by virtue of its built-in resilience, exerts a powerful frictional grip on the rod to preventv axial slipping of the scraper thereon.

The present invention contemplates an embodiment wherein the scraper is made of a plastic material having springlike qualities which provide the scraper With the aforementioned tight grip on the sucker rod, and the inention further contemplates anotherA embodiment wherein the scraper consists of a similar plastic structure butI including in addition thereto one or more springsteel clips designed to augment thegrip of the resilient scraper f,

on the rod. t It is a further very important object of the present inven-g tion to provide anopposed-slot scraper which is moldedfrom a plastic which, in the presence of high temperatures and corrosive uids often found in oil wells, exhibitsexcellent stability with respect to its mechanical dimensions; it is an electrical insulator to prevent electrolysis; and in addition has excellent acid and oil resistant properties. The range of plastics which exhibit satisfactory physical and chemical properties,v and at the same time'may be molded to the desired form, include'the following:

Polyvinylidene chloride Polyamides; molding type, nylon 10,001, known as Zytel Polytetra-uoro ethylene Polychloro-tritiuoro ethylene Polymethyl4 alpha chloro-acrylate Polyester diallyl phthalate Poly ac etal resin v Oneof the properties exhibited'by Scrapers madevof one ofthe above plastics includes the important characteristic that the very parain which thedevice according to the present invention is intended4 to fscrapexhas verynlittle tendency to stick to the plasticsrfacessince these surfaces are very smooth and non porous. This is one important and unobvious property which distinguishes the so as to provide a thicker plastic pad between the metal clip and the bore of the boss, which thicker plastic pad provides better protection of the clip against corrosion by; l well iiuids, and which thicker pad may be placed under,l

compression against the surface of the rod by the steel clip so as to provide an improved grip on the rod. The improved spring clip has also been provided with two. tangential portions which extend outwardly on each side' of the slot through the boss and provide backing for the slot, which backing tends to force the walls of the slot to-y gether in such a way as to provide an increased grip on the rod. The improved clip not only provides a better grip on the rod employing lighter-gauge metal, but in addition permits a wider tolerance in the dimensions of the clip during manufacture thereof as a result of the thicker pad of plastic material disposed between the metal clip and the bore of the boss. It is another object of the present invention to provide a rscraper having transverse end surfaces which -are rounded at their outer peripheries so as to provide the scraper with tapered ends designed to reduce the tendency of .the latter to snag upon tubing joints in order to facili; tate the free reciprocation of the device within the tubing.-

Further objects and advantages of the invention will become apparent during the following discussion of the drawing wherein: A

Figure l is a perspective view of one of the present parain Scrapers mounted on a sucker rod and located Y within a length of pump tubing, the tubing being shown lower boss of the scraper in Fig. 3 being shown particu,

larly in cross section. Y

` Fig. 4 is a longitudinal section view through the paraini scraper taken along line 4 4 of Fig. 3.

Fig. 5 is a cross section taken along line 5 5 of Pig. 2.?

,Fig 6 is an enlarged perspective of the spring clip as included in the illustrations of Figs. 2, v3, 4 and 5.

Referring now to the drawing, Fig. l shows a sucker'l rod R disposed-within a length of pump tubing T, the latterbe'ing shown in cross section Aso as to illustrate-Nan, parafn lscraper according` to the present invention lo. cated within the tubing. The paraffin scraper illustrated.,

in Fig. l may or may not contain springclips intended to increase the grip of the scraper on the sucker rod R. The parain scraper itself comprises a body l hsv-r i 'assenza can be seen in Figs. 4 and 5V which illustrate that the body 1 comprises a spiral blade *having sides laland having aniinner `peripheral surface lrband` an outerpe-` ripheralsurface 1c whichA will be more fully described The side `surfacesf'ljalrof ,theiblade `taperV j toward each other as they extendoutwardly awayfromthe y central axis-of thescraper and are smoothlyV curved so" as to facilitate the flow of well `u'ids `therepast 'and s0V hereinafter.

a's`to discourage the tendency of paraiiinto build up on the surface of the scraper.A The outer peripheral surface 1c comprises a bearing surface which is"comparatively narrow and which coincides witha cylinder coaxiahwith the scraper. The bearingsurface lctravels against the inner wall of thetubing T Vduring scraping'of paralin deposits'therefrom. Therbearing surface 1calso serves the' additional purpose of abutting ,the walls of the Ytubing T to 'center the suckerrod R therein,and the ends 1d of the bearing surface 1c curve inwardly and blend into the vbosses 2. j j 'Y The spring clip 3 lis best illustrated in Fig. 6,@although clipy3 is generally Clshaped'and in addition isprovided with crimped-in ends V3a which increase the grip ofthe Vmaterial being molded nylon, and said spring clip being metal and embedded in the nylon during molding of the scraper. Y Y K Y 4. In a scraper as set forthV in claim 1,7the diameter ofj the sucker rod being slightly greater than the diameters of said bores and the widths of said openings.

5. In a scraperas setforth in claim `4, said clips terminating in'tangentially disposed .portions on each side of the opening.. therethrough and said, tangential portions Vextendi'ngradially outwardly parallel with the'walls of the Vslot in the boss.`

6. In a scraper yasset forth claim 4, the longitudinal ends-of the clip being -crimpedinwardly toward'the-b'ore Y and slot to stiifen` the` spring grip. f

VitsV installation in the bosses of'the paraffin scraper isfA illustrated inFigs. 2 through 5 inclusive. The spring clip V3 without the necessity of increasing the gauge of metal from which the clip is manufactured. 4In addi-7 tion, as shown in Fig. 5 the clip includes two tangentiallyY disposed portions 3b Yadapted to tmderliei the walls of the slot-2b of the boss Z. Each of the hossesvz; has a bore 2a which together Vwith the inner Vperipheralsurface 1b;

ofthe blade define an axial opening throughlthe scraperV bod'y. 1 j

Although the drawing illustrates va paraiiinscraper having only one -turn ofthe spiral body l about ythe sucker Vrod R, .it is to be understoodl that the invention con-' 7.'ln a scraper as set forth in claim l, the inner periphery of said Lblade having a rod engaging surface smoothly joining the bore in each boss and complementary in shape with and partially surrounding said rod at any cross-section taken' through the scraper normal to theh longitudinal axis thereof.

8. In a scraper assetfoith in claim 7, theouter pei riphery offsaid Ablade comprising a bearing surface lying in a cylinder coaxial with the axes of said bores, and the endsy of-the blade `andjof the bosses-being rounded inwardlyu fromvjtheir `peripheral surfaces and terminating intransversely/disposed end surfaces.

9.A In a `scraper as set forth in claim l, the` slotsV in the -tworbosses facing. inmutually opposite directions transversely `ofl the f axis of the scraper.

10;` A-onepiece molded. plastic parafiin scraper havin'g an axial opening therethrough. to receive and fric# tionalhkf'gripY a lsucker rod,w said scraper comprising vanl open -helicalscraping blade of at least one turn; and

rod-gripping ends each comprising a boss molded to one end of Vthe biadeandhaving a bore formed by said axial opening thediameter of each bore being slightly Y smaller thanthe diameter of the rod; and each boss havtemplates other embodiments ,whereinVV a plurality ofV spaced convolutions of. `thespiral body 1 maybe employed. The s'lot 2b Vin each of the bosses 2 should face away from the location of the junction ofthe body I Withthe.

boss V2. In-a` short paraiiin scraper employing only one Y turn of the spiral, as shown. in the.drawings',`it -is` desirable to have theV two slots 2b face in mutually opposite directions transversely of the axis of thescraper.'

However,` in the case of `longer scrapersembodying'addi-` tional convolutions Vof the spiralbody 1, the` direction in which the slots 2b face with respect -to one another becomes `liess important.

' lI'do 'not limit myinvention to the Vexact formshown in `the-'drawingY for obviously changes may be made there? in within the scope of the following claims.

` Ivclaim:

1. A parain scraper offdeformable'material adapte-dv Y to'spiral. around and frictionally `grip a sucker rod, .com-j 'prising an open helical scraping blade .standing normal at` each point along-its lengthto the surface ofV the rod, the adjacent points Von the *blade Abeing fmutuf ing a slot through its" side wall into Ythe bore andslightly narrower xthjanftbediameter-'of therod, the slot in each .boss-being circumferentially spaced from the junction of the blade r'with the boss.

" plastic is nylon.VV

cross-se`ction= takeny through the scraper normalA to the periphery ofV said Vblade` comprising a bearing surface lying'nfacylinderlcoaxial with the axis of said bores, .theYbladeland-the bossesbeing rounded inwardly/from i their"outerf'p'eripheral surfaces and ftermn'atingin trans allymspaced axially Vof the scraper;Y two rod grip-y f ping'vends each comprising a bossfsubstantiallyenf..

compassing the rod and having a bore ;.therethroug'h aligned 'with the axis of the helical Vblade and ofldiameter` nogreater than that of the rod, the blade `terminating tceaeh. end in an adjacentrboss andeach boss-having l a slot through its side wall into said 'bore and forming an opening no wider than the'diameterof`said':`rod;1and a G-shapedspring clip embedded inV eachboss surrounding Y.

a lengthJofeach bore'an'd having an opening registeringV iViththe adjacentjsloti a 2. Ina scraper-as set forth in claimV 1,` said `deformable material fbeing a molded plastic, and said spr'ingv'clip being metal and embedded in said plastic during-molding Y of-fthe scraper.

- `3. InaY scraper asV set Vfortl'irin claim 1,psaidi.deformable` 12. Inai` scraper-as"isetfforth'in claim y1.0i theinner periphery ofsaid 4-blade`-`having a roden'gaging surface smoothly vjoining the borein eachbossand complementary' in shape with and partially surrounding the rod at any longitudinalfaxis thereof. Y

" i3. Ina's'craper-as set" forth in claim 12,` thev outerver'sely disposedllend surfaces." 1 l "j14."In=alscraper asisetlfortii-inclaim 10; theslots'j in thetwo-bosses' opening; `in mutuallyV opposite radial dircctions-frmfthe axis ofjthefrscraper. Y

' References-.Cited.'inthezle of. thispatentf. 

